It should work if you had a backup of the xampp directory before the crash but only up to the point you did the backup. So if your backup is a week old then that is the point at which your forum will work from.
Because you mention "i have a big forum and big website that dapend on my server"
then running this sort of operation on your home PC (Windows) is not recommended as Windows is prone to crashing, as you have just found out and would be a worry for any sort of critical server operation.
Linux however is another ball game entirely and is very stable and reliable in a web server situation. XAMPP can be used on a linux box but LAMPP (Linux Apache mySQL php Pearl) is an integral part of most linux distros and is the preferred server setup for critical applications.
Have you tried a free hosted alternative or even a cheap hosted server? Cheap as in only a few bucks a month (the price of a cup of coffee) gets you a reliable shared hosting service these days. As credit cards are usually required for payment to a hosting company there is often an age barrier to this method, 18 being the usual age condition for CC ownership. Parents though often come to the rescue on this point.
Post more info if you want more help on your crash issue.